#include <iostream>
#include <vector>   // Use Vector Class

int main() {
    using namespace std;
    vector<int> vi; // create x zero-size array of int
    vi.push_back(4);
    int n;
    cin >> n;
    vector<double> vd(n);   // create an array of n doubles
    for (int i = 1; i <= n; ++i) {
        vd[i - 1] = (i + (n >> 1)) / 10.0;
    }
    cout << vi[0] << endl;
    for (double d: vd) {
        cout << d << " ";
    }
    cout << endl;
    return 0;
}